1. Field of the Invention
This invention relates to a photographic camera equipped with a zoom lens and a zoom ratio adjusting device for the camera.
2. Description of Related Art
Various types of compact cameras equipped with zoom lenses have been put on the market. Motor driven compact cameras of this kind are equipped with a zoom ratio adjusting switch button for actuating an electric motor in opposite direction to drive the zoom lens to adjust a zoom ratio. One type of motor driven compact camera has a single zoom ratio adjusting switch button for continuously moving the zoom lens back and forth to continuously varying a zoom ratio between a telephoto end and a wide-angle end while the zoom ratio adjusting switch button remains operated. This type of motor driven compact camera takes a relatively long time until the zoom lens is placed at a desired zoom ratio. Another type of motor driven compact camera has has two zoom ratio adjusting switch buttons, namely a telephoto switch button and a wide-angle switch button, which is desirable to change the zoom ratio in any direction between a telephoto end and a wide-angle end from any lens position. However, providing two zoom ratio adjusting switch buttons is accompanied by an increase in the number of parts, which is always undesirable for compact cameras having a demand that it is made with a simple structure and manufactured at costs as low as possible.
In order to solve the structural and economic problems of the conventional compact cameras, it has been proposed to incorporate a single zoom ratio adjusting member movable between a telephoto end position and a wide-angle end position provided on opposite sides of a neutral position for actuating a zoom lens drive means such as an electric motor to drive the zoom lens toward a telephoto end while operated to the telephoto end position from the neutral position and to drive the zoom lens toward the wide-angle end while operated to the wide-angle end position from the neutral position. While the zoom ratio adjusting device enables the photographer to adjust the zoom ratio between the telephoto end and the wide-angle end from any lens position, however, it must be accompanied by means for returning the zoom ratio adjusting member to the neutral position after a conclusion of zoom ratio adjustment and holding it in the neutral position. This means includes metal springs in most cases, which increases manufacturing costs of the compact camera.